How to protect your brain and heart with adequate vitamin D

Best known for its role in maintaining calcium balance in the body, vitamin D has increasingly emerged as a critical player in defending us against a whole host of other chronic conditions including high blood pressure, heart disease and cancer.

Vitamin D deficiency is associated with cognitive decline

If that wasn’t enough emerging science has enabled a better understanding of how vitamin D plays a pivotal role in brain health from autoimmune conditions such as multiple sclerosis to depression and anxiety, cognitive function and dementia including the debilitating condition Alzheimer’s disease. (1, 2, 3)

Scientists have described over 10 mechanisms showing potential clinical effect of vitamin D supplementation on the development of Alzheimer’s disease

These findings are not surprising when it was discovered that vitamin D behaves more like a hormone meaning it can affect the functioning of different organs and tissues. In fact when needed all metabolically active organs including the brain can convert calcidiol – the storage from of vitamin D (25-hydroxyvitamin D or 25 OH D) to the active form calcitriol (1,25 dihydroxy vitamin D or 1,25 (OH)2 D). Vitamin D is derived from the sun’s UVB rays reacting with a molecule close to the surface of the skin. Once activated it attaches to cell receptors and essentially turns on or off over 10% of our genes involved in various processes including inflammation, immune system and detoxification. (3) It can also produce hundreds of anti-microbial peptides that function as an internal broad-spectrum antibiotic.(4). This makes vitamin D a powerful ally in our health maintenance toolkit

With such a widespread effect you would expect that ensuring vitamin D sufficiency would be top of mind as a treatment for any chronic health condition or as a preventive measure for neurodegenerative disease. Not so fast.

Defining vitamin D sufficiencyVitamin D supplements for optimal health

The Institute of Medicine (IOM) defines a vitamin D sufficiency level of > 20ng/mL which according to population data puts one-third of people at risk for clinical inadequacy. (5) For optimal calcium metabolism and bone health experts agree that a serum concentration > 30ng/mL is likely necessary which would place an estimated one billion people worldwide in the insufficiency category. A study performed in 18 countries showed that 64% of women had levels below 30 ng/mL. (6)

A vitamin D action group of scientists and medical professionals are lobbying for an increase in the US recommended dietary allowance which currently stands at 600-800 IU per day. They maintain the current recommendation is woefully inadequate for preventing chronic disease and achieving a serum concentration of 40-60 ng/ML which science points to as the sweet spot for fighting these conditions. (7) They contest that of the 30 leading causes of death in the United States in 2010, 19 have been linked to low vitamin D status. (8)

Intakes of 700-1000 IU have been shown to achieve 25(OH) D levels of 36- 40 ng/ML. (9) In order to achieve the higher level of 40-60 ng/mL level it is suggested that we need at least 4000 IU of vitamin D3 per day from various sources.(10) This amount is well within the Institute of Medicine’s no-observed adverse effect (NOAEL) of 10,000 IU and sits at the safe upper limit set at 4000 IU by the IOM as well as the EFSA in Europe. (11,12,13,14) Taking more than this safe upper limit level should be accompanied by regular monitoring according the vitamin D council.(15)

Sources of Vitamin D

Sources of vitamin D3 Getting adequate amounts of vitamin D in the modern diet is not easy when it is only found in quantity in a limited number of foods that are not regularly consumed e.g. 3 ounces of salmon or swordfish contain around 500 IU. By comparison eggs contain about 41 IU and 1 ounce of cheese less than 10 IU.  One tablespoon of cod liver oil contains nearly 1400 IU. (16) In order to avoid deficiency vitamin D is commonly added back by food companies into foods that have lost this vital nutrient during processing. However, the form of vitamin D used is typically D2 (ergocalciferol) which is not as effective or healthful to the body.(17)

Some argue the best source of vitamin D is from the sun. As a benchmark 15-20 minutes of sun during the middle hours of the day exposing a good amount of unprotected skin provides the equivalent of 10-15,000 IU per day. (18,19) It’s important to apply sunscreen when the skin is very slightly pink and always ahead of starting to burn.  Since the body regulates the conversion of vitamin D to its active form it’s generally considered a safe way to get vitamin D. The amount of vitamin absorbed will vary depending on the latitude of where you live, the season, the sun’s angle and wavelength, your skin color, your weight and your age.(20)

Supplements are another good choice

Many supplements contain 1000 IU vitamin D3 per serving which is well within the safety margins established in clinical studies.  Things to look for when choosing a supplement include quality manufacturing standards, third party testing certifications and seals of approval. This will help reassure you that the product has been made with attention to quality, safety and efficacy. Some testing labs can also advise on the absence of heavy metal and genetically modified ingredients. (21) Also, check the label for added fillers, preservatives, dyes and sweeteners which can contribute to sensitivity reactions.

Vitamin D co-factors

Most vitamins and minerals work synergistically together so it’s important to note that if you are taking vitamin D3 you should also take vitamin K2 for two reasons.  Vitamin K2 works in concert with D3 to direct and maintain calcium in your bones and away from arteries and other soft tissues.(22) Taking both together helps with strengthening your bones and protecting your heart.  Vitamin K2 and vitamin A also lower the toxicity threshold of vitamin D3, so taking these two vitamins adds extra security when taking extra D3 to increase your serum concentration levels to support chronic disease conditions.(23)

Magnesium is a mineral involved in over 300 enzyme reactions powering your metabolism. One of those reactions is as a co-factor for the conversion of vitamin D into its active form.(24) It’s therefore important to ensure that all that sunlight does not go to waste by maintaining an adequate intake of magnesium.  Look for magnesium citrate or glycinate for superior absorption.

The Bottom Line

  • Vitamin D3 sufficiency is vital for supporting healthy bones, a healthy heart and a healthy brain
  • A vitamin D serum concentration level of >30 ng/mL supports good bone health and can be achieved at 1000 IU per day
  • Sufficiency for fighting chronic conditions is maintaining a serum concentration between 40-60 ng/mL, according to research
  • Supplementing at the safe Upper Limit of 4000 IU per day will help approach these levels
  • Consider having your vitamin D3 (25 OH D) level tested twice a year to establish a baseline and monitor your target
  • If you take a vitamin D3 supplement take vitamin K2 and magnesium as well.

  1. Schloegl M, Holick MF. Vitamin D and neurocognitive function. Clinical interventions in aging. 2014: 9: 559-568
  2. Ascerio A et al. Vitamin D as an early predictor of multiple sclerosis activity and progression. JAMA Neurol. 2014 Mar;71(3):306-14. doi: 10.1001/jamaneurol.2013.5993.
  3. Khanh VQL, Lan THN. The Role of Vitamin D in Alzheimer’s Disease: Possible Genetic and Cell Signaling Mechanisms. Am J Clin Nutr; 2012 95 (1):163-178. doi: 10.3945/ajcn.111.017137
  4. Liu PT et al. Cutting Edge: Vitamin D-Mediated Human Antimicrobial Activity against Mycobacterium tuberculosis Is Dependent on the Induction of Cathelicidin. J Immunol.2007; 179 (4): 2060-2063. doi: 10.4049/jimmunol.179.4.2060
  6. Holick MF. Vitamin D: a D-Lightful health perspective. Doi:10.111/j.1753-4887.2008.00104x
  8. Baggerly CA et al. Sunlight and Vitamin D: Necessary for Public Health. J Am Nutr. 2015; 34:4, 359-365, DOI: 10.1080/07315724.2015.1039866
  9. Bischoff-Ferrari HA et al. Estimation of optimal serum concentrations of 25-hydroxyvitamin Df or multiple health outcomes. A J Clin Nutr. 2006; 84(1):18-28
  11. Vieth R. Vitamin D Toxicity, policy and science. J bone Min Res. 2007(22) s2. Doi:10.1359/JBMR.07S221
  14. Hathcock JN et al. Risk assessment for vitamin D. Am J Clin Nutr. 2007; 85 (1): 6-18
  16. NIH website. Vitamin D Fact Sheet for Health professionals. Available at:
  17. Trang HM et al. Evidence that vitamin D3 increases serum 25-hydroxyvitamin D more efficiently than does vitamin D2. Am J Clin Nutr.1998;68(4):854-858
  19. Reichrath J, Nuerenberg B Cutaneous vitamin D synthesis versus skin cancer development. Dermatoendocrinol. 2009 Sep-Oct; 1(5): 253–261
  20. Holick MF. Vitamin D: a D-Lightful health perspective. Doi:10.111/j.1753-4887.2008.00104x
  22. Kidd PM. Vitamins D and K as Pleiotropic Nutrients: Clinical Importance to the Skeletal and Cardiovascular Systems and Preliminary Evidence for Synergy. Altern Med Rev; 2010;15(3):199-222
  24. Zitterman A Magnesium deficit – overlooked cause of low vitamin D status? BMC Medicine 2013;11:229.doi:10.1186/1741-7015-11-229

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